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通过含氯盐与亚硝酸盐钢筋混凝土加速腐蚀试验肉眼观察确定了腐蚀等级,并结合阳极极化、电极电位、腐蚀面积率和质量损失率综合确定抑制钢筋腐蚀所需临界摩尔比n(NO–2)/n(Cl–)。结果表明:混凝土中钢筋腐蚀的评价方法不同,临界n(NO2–)/n(Cl–)有一定的差异,混凝土中钢筋质量损失率与腐蚀面积率之比可以很好地评价钢筋坑蚀程度;随着混凝土中氯离子含量的增加,抑制钢筋腐蚀所需临界n(NO–2)/n(Cl–)提高,在氯离子含量小于4kg/m3范围内,n(NO2–)/n(Cl–)小于0.4时抑制钢筋腐蚀效果不明显,有时加速宏电池腐蚀;当n(NO2–)/n(Cl–)大于1.2时可以完全抑制钢筋腐蚀。同时明确了模拟混凝土孔溶液中临界n(NO2–)/n(Cl–)小于实际混凝土中临界n(NO–2)/n(Cl–)。
Corrosion grade was determined by macroscopical observation with accelerated corrosion test of chloride salt and nitrite reinforced concrete. The critical molar ratio n (NO-2) of inhibiting corrosion of steel was determined synthetically by combining anodic polarization, electrode potential, corrosion area ratio and mass loss rate. 2) / n (Cl-). The results show that the evaluation method of steel corrosion in concrete is different, and the critical n (NO2 -) / n (Cl -) has some differences. The ratio of steel mass loss and corrosion area ratio in concrete can well evaluate the corrosion degree of steel pits ; With the increase of chloride ion content in concrete, the critical n (NO-2) / n (Cl-) needed to restrain the corrosion of reinforced steel increased. When the content of chloride ion was less than 4kg / Cl-) is less than 0.4, the effect of inhibiting corrosion of steel bar is not obvious, sometimes accelerating the corrosion of macro cell; when n (NO2 -) / n (Cl-) is more than 1.2, the corrosion of steel bar can be completely inhibited. At the same time, the critical n (NO2 -) / n (Cl-) in the simulated concrete pore solution is also less than the critical n (NO-2) / n (Cl-) in the concrete.